Winding Fault Detection System and Method

This application claims priority to Indian Provisional Patent Application No. 202411044635, filed Jun. 10, 2024, the disclosure of which is hereby incorporated by reference in its entirety.

The present disclosure relates generally to fault detection, and, more particularly to winding fault detection.

Winding faults occur when a portion of insulation surrounding individual windings wears down or short circuit occurs between winding conductors. A winding fault in a motor, for example, effectively reduces the number of turns in the affected phase of a multi-phase motor, which can unbalance the motor, reduce the performance of the motor, and/or damage the motor. As such, there is a need to detect winding faults and take precautions in response thereto.

One aspect of the present disclosure provides method for determining a winding fault in a multi-wound electrical device. A first instantaneous current in first set of windings of the multi-wound electrical device is received. A second instantaneous current in second set of windings of the multi-wound electrical device is received. First sequence components are determined from the first instantaneous current. Second sequence components are determined from the second instantaneous current. The first sequence components are compared with second sequence components. A winding fault in the multi-wound electrical device is determined when a difference in the first sequence components and second sequence components is greater than a predetermined value.

In accordance with further aspects of the disclosure, a system for determining a winding fault in a multi-would electrical device, comprising: a memory; and a processor connected to the memory, wherein the processor is configured to: receive a first instantaneous current in first set of windings of the multi-wound electrical device; receive a second instantaneous current in second set of windings of the multi-wound electrical device; determine first sequence components from the first instantaneous current; determine second sequence components from the second instantaneous current; compare the first sequence components with second sequence components; and determine a winding fault in the multi-wound electrical device when a difference in the first sequence components and second sequence components is greater than a predetermined value.

In accordance with still further aspects of the disclosure, a computer-readable medium that stores a set of instructions which when executed perform a method executed by the set of instructions comprising: receiving a first instantaneous current in first set of windings of the multi-wound electrical device; receiving a second instantaneous current in second set of windings of the multi-wound electrical device; determining first sequence components from the first instantaneous current; determining second sequence components from the second instantaneous current; comparing the first sequence components with second sequence components; and determining a winding fault in the multi-wound electrical device when a difference in the first sequence components and second sequence components is greater than a predetermined value.

These and other features and advantages will be apparent from a reading of the following detailed description and a review of the associated drawings. A variety of additional aspects will be set forth in the description that follows. These aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad concepts upon which the embodiments disclosed herein are based.

Reference will now be made in detail to exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like structure.

The disclosure provides techniques to determine winding faults in multi-wound electrical devices (for example, motors, generators, transformers, etc.). In a multi-wound electrical device, following types of winding faults can occur: a phase-to-ground (PG) fault, a phase-to-phase (PP) fault (also referred to as a winding-to-winding (WW) fault), an inter-turn (IT) fault, a phase-to-phase (PP) and a PG fault in both the winding set. The disclosure provides techniques to detect these types of winding faults, and estimate a severity of these winding faults in a multi-wound electrical device. Current sensors are used for detection of these faults. In one example aspects, the winding faults are determined by comparing features of one set of winding with another set of windings of a multi-wound electrical device. Determining winding faults by comparing features of one set of winding are compared with another set of windings mitigates the effect of temperature, load, and other operational and environmental factors on winding fault detection. Aspects of the disclosure further provide techniques to distinguish between a WW fault and a PG fault in two windings. In addition, aspects of the disclosure provide techniques for estimating fault current resulting from the determined winding faults. Estimated fault current may be used to determine an actual effect of the detected fault on working of the electrical device and/or determining one or more corrective actions.

is a diagram of a sectional representation of an example multi-wound electrical device (that is, a dual wound motor) in accordance with principles of the present disclosure.is a diagram of an alternate sectional representation of dual-wound motorof. As illustrated in, dual-wound motorincludes two set of windings, for example, first set of windingsand a second set of windings. First set of windingsmay include three windings represented as A, B, and C. Second set of windingsmay also include three windings represented as A′, B′, and C′. First set of windingsmay be separated from second set of windingsby a phase insulation. Although motoris shown to include only two set of windings, motormay include more than two set of windings. In addition, the techniques are being discussed with reference to motor, it may be applicable in any electrical device that includes more than one winding, for example, a transformer, a generator, etc.

is a diagram illustrating a fault detection system. Fault detection systemmay detect winding faults in a multi-wound electrical device, for example, dual-wound motorof. As shown in, fault detection systemmay include current sensorsand a fault detector. Current sensorsmay be associated with each winding of motorand measure an instantaneous current in the associated winding. Current sensorsmay provide the measured current to fault detector. Fault detectormay determine, from the measured current in windings of motor, to determine winding faults in motor.

In one implementation, fault detectorconverts measured current into a “positive sequence” (e.g., forward rotating), “negative sequence” (e.g., reverse rotating), and a “zero sequence” (e.g., common or shared) component. When a winding fault occurs in any winding of motor, the positive sequence component is diminished, while negative sequence and/or zero sequence components are increased. Although the presence of negative sequence and/or zero sequence components may be good indicators of a winding fault, in real-world three-phase systems are rarely (if ever) perfectly balanced. As a result, a certain amount of positive sequence and/or zero sequence components exist. Therefore, fault detectormay determine a baseline values for the positive sequence component, the negative sequence component, and the zero sequence component.

If motoris healthy (i.e., no winding faults), the positive sequence component may dominate, and the negative and zero sequences may be negligible (that is, equal to or closer to respective baseline values). When a winding fault occurs, the positive sequence component magnitude may decrease, and the negative sequence component and/or the zero sequence component may increase. However, all windings (that is, first windingand second winding) to motorare in the same environment and load condition. Hence the sequence components of one set of windings (that is, first set of windings) may be compared with the sequence components of another set of windings (that is, second set of windings) to identify any winding fault.

The elements described above of fault detection system(that is, current sensorsand fault detector) may be practiced in a hardware and/or in software (including firmware, resident software, micro-code, etc.) or in any other circuits or systems. The elements of fault detection systemmay be practiced in electrical circuits comprising discrete electronic elements, packaged or integrated electronic chips containing logic gates, a circuit utilizing a microprocessor, or on a single chip containing electronic elements or microprocessors. Furthermore, the elements of fault detection systemmay also be practiced using other technologies capable of performing logical operations such as, for example, AND, OR, and NOT, including but not limited to, mechanical, optical, fluidic, and quantum technologies. As described in greater detail below with respect to, the elements of fault detection systemmay be practiced in a computing device.

is a flow diagram of a methodfor determining a winding fault in an electrical device, for example, motordescribed with reference to. In certain examples, methodcan be performed by fault detector. In other examples, methodis performed by a processor connected to a memory device. The memory device may store the instructions which, when executed by the processor, perform method. Ways to implement the stages of methodwill be described in greater detail below.

At stageof method, a first instantaneous current in first set of windings of the multi-wound electrical device is received. For example, fault detectormay receive the first instantaneous current in first set of windingsof motor. The first instantaneous current is measured by current sensorsand sent to fault detector.

At stageof method, a second instantaneous current in second set of windings of the multi-wound electrical device is received. For example, fault detectormay receive the second instantaneous current in second set of windingsof motor. The second instantaneous current is measured by current sensorsand sent to fault detector.

At stageof method, first sequence components are determined from the first instantaneous current. For example, fault detectormay determine a first positive sequence component, a first negative sequence component, and a first zero sequence component from the first instantaneous current.

At stageof method, second sequence components are determined from the second instantaneous current. For example, fault detectormay determine a second positive sequence component, a second negative sequence component, and a second zero sequence component from the second instantaneous current.

At stageof method, the first sequence components are compared with second sequence components. For example, the first zero sequence is compared with the second zero sequence component. In addition, the first negative sequence is compared with the second negative component. The comparison may include determined a difference between the respective sequence components.

At stageof method, a winding fault is determined in the multi-wound electrical device when a difference in the first sequence components and second sequence components is greater than a predetermined value. That is:

=|Sequence component of1−Sequence component of2|>Baseline (Fault).

=|Sequence component of1−Sequence component of2|<Baseline (healthy).

In example aspects, increase in the value of D indicates an increased fault severity.is a diagram of a Table 1 illustrating first example measurementscorresponding to two windings of motor. As shown in, the zero sequence component and the negative sequence component of both the winding are different from that of a healthy motor (indicated as 255). In addition, and as shown in Table 1, an increase in the difference may be indicative of increase in fault severity. As discussed in the following sections of the disclosure, a type of the winding fault (shown as a WW fault in Table 1) is also determined based on comparing the sequence components of windings of motor.

is a flow diagram of a methodfor determining a winding fault in an electrical device, for example, motordescribed with reference to. In certain examples, methodcan be performed by fault detector. In other examples, methodis performed by a processor connected to a memory device. The memory device may store the instructions which, when executed by the processor, perform method. Ways to implement the stages of methodwill be described in greater detail below.

At stageof method, instantaneous currents in each of first set of windingsand second set of windingsare received. The instantaneous currents are sensed by current sensorsand can be represented as i, iand ifor first sent of windingsand as i, iand ifor the second set of windings. The instantaneous currents are then provided to fault detector.

At stageof method, sequence components are determined for the instantaneous currents for both first and second set of windings. For example, the signal components of the sensed instantaneous current can be converted into a “positive sequence” (e.g., forward rotating), “negative sequence” (e.g., reverse rotating), and a “zero sequence” (e.g., common or shared) component for both first set of windingsand second set of windings.

At stageof method, the zero sequence component of first set of windings(that is, a first zero sequence component) is compared with the zero sequence component of second set of windings(that is, a second zero sequence component). During comparison it may be determined whether the difference between the first zero sequence component and the second zero sequence component is less than a first predetermined value. That is, whether:

where Irepresents the first zero sequence component of first set of windings, Irepresents the second zero sequence component of second set of windings, and L1 represents the first predetermined value. In some examples, the first predetermined value is a baseline value for the zero sequence components.

Atof method, in response to determining that the difference between the first zero sequence component and the second zero sequence component is not less than the first predetermined value at stage, a likelihood of a PG fault being high is determined. For example, for a healthy motor, the difference between the zero sequence components for all the windings is less than a baseline value. The zero sequence component may increase when there is a fault between a winding and the ground with a fault current flowing from the winding to the ground.is a diagram of a Table 2 illustrating second example measurementscorresponding to a PG fault.

As shown in Table 2, for a healthy motor, both the first zero sequence component and the second zero sequence components are approximately equal to 0. However, and as shown in Table 2, for a leakage current of 30 mA, the second zero sequence component of second set of windingsis 3. The leakage current is because of a winding fault, that is, a PG fault in second set of windings of motor. Moreover, for a leakage current of 60 mA, the second zero sequence component of second set of windingsis 5 and increases to 8 when leakage current increases to 90 mA. On the other hand, the first zero sequence component of first set of windingsremains approximately equal to 0 irrespective of the leakage current. Therefore, and as shown in Table 2, for a PG fault, a difference between the first zero sequence component of first set of windingsand the second zero sequence component of second set of windingsis higher than 0 (indicated as 377) and the severity increases with increase in the leakage current.

At stageof method, an alarm is generated in response to determining the likelihood of the PG fault being high. The alarm may be an audible alarm, for example, a siren, or a visible alarm, for example, a blinking red light, or both the audible alarm and a visible alarm.

In response to determining that the difference between the first zero sequence component of first set of windingsand the second zero sequence component of second set of windingsis less than the first predetermined value at stage, methodproceeds to stagewhere the first negative sequence component of first set of windingsis compared with the second negative sequence component of second set of windings. During the comparison, it may be determined whether the difference between the first negative sequence component and the second negative sequence component is less than a second predetermined value. That is, whether:

where Irepresents the first negative sequence component of first set of windings, Irepresents the second negative sequence component of second set of windings, and L2 represents the second predetermined value. In some examples, the second predetermined value is a baseline value for the negative sequence components of windings of motor.

Atof method, in response to determining that the difference between the first negative sequence component and the second negative sequence component is not less than the second predetermined value, a likelihood of an IT fault and/or a PP fault being high is determined.is a diagram of a Table 3 illustrating third example measurementscorresponding to a PP fault.

As shown in Table 3 of, for a healthy motor, both the first negative sequence component and the second negative component are approximately equal to 0 for both first set of windingsand second set of windingsrespectively. However, and as shown in Table 3, for a leakage current of 30 mA, the first negative sequence component of first set of windingsis at 7. The leakage current is because of a winding fault, that is, IT fault and/or a PP fault in the windings of motor. For example, because of a short circuit between a phase of first set of windingsand a phase of second set of windings, a fault current may flow between first set of windingsand second set of windings resulting in deviation of the negative sequence components. The increase in the fault current may result in increased deviation.

For example, and as shown in Table 3, for a leakage current of 60 mA, the first negative sequence component of first set of windingsis 13 and increases to 18 when leakage current increases to 90 mA. On the other hand, the second negative sequence component of second set of windingsremains approximately equal to 0 or closer to 0 (that is, 1) irrespective of the leakage current. Therefore, and as indicated in Table 3, a difference between the first negative sequence component of first set of windingsand the second negative sequence component of second set of windingsis higher than 0 and increases with increase in the leakage current (indicated as 382).

Once having determined the likelihood of the PP fault being high at stage, methodmay, at stage, generate an alarm. The alarm can be audible alarm, a visible alarm, or a combination of both the audible and visible alarm.

In response to determining that the difference between the first negative sequence component and the second negative sequence component is less than the second predetermined value at stage, methodproceeds to stagewhere a sum of currents for both first set of windingsand second set of windingsis determined. The sum (Zt) of currents for both first set of windingsand second set of windingsis determined is determined as:

At stageof method, the sum (Zt) is compared with a baseline value to determine whether the sum (Zt) is greater than the baseline value. In response to determining that the sum (Zt) is greater than the baseline value at stage, a likelihood of a PG fault in both first set of windingsand second set of windingsis determined at stage. For example, the total current of first set of windingsand second set of windingsmay be more than the baseline value because of faults in both set of windings and fault currents flowing from each of first set of windingsand second set of windingsto the ground.

In response to determining that the sum (Zt) is greater than the baseline value at stage, an alarm is generated at stageof methodindicating a likelihood of the PG fault in both first set of windingsand second set of windings. Once having determined the likelihood of the PG fault being high in both first set of windingsand second set of windingsat stage, methodmay, at stage, generate an alarm. The alarm can be audible alarm, a visible alarm, or a combination of both the audible and visible alarm.

In response to determining that the sum (Zt) is not greater than the baseline value at stage, methodproceeds to stagewhere the zero sequence component of each of first set of windingsand second set of windingsis compared with a respective baseline value. That is:

=|Zero Sequence component of1/2−Zero Sequence component of1/2 of healthy system|

If a value of Z is not closer to zero (that is, when the zero sequence component of any of first set of windingsand second set of windingsis greater than the respective baseline value), then the WW fault is determined in motorat stage. That is:

>baseline &≈0→fault.

>baseline &>0→fault.

In response to determining the WW fault at stage, an alarm is raised at stage. The alarm can be audible alarm, a visible alarm, or a combination of both the audible and visible alarm.